price/performance for ic engines?

[nostatic]

a friend of mine sent me the following question. Anyone got any ideas?

Silicon chips have followed an exponential improvement – what’s it been for internal combustion engines? Of course, there are many factors that have to be traded off (fuel efficiency, emissions, power output) and so there isn’t a simple way to measure progress. But just take power to weight ratio. I assume it’s improved a lot. Is it still growing strong, or is it asymptotically approaching some theoretical limit?

[widebody911]

I don't think weight would have anything to do with it, but rather hp:cc I'm not a physicist, and I don't play one on TV, but I think the IC engine is inherently restricted by chemistry and physics. Moore's law doesn't have the same limitations.

[lendaddy]

I believe it's a matter of thermal efficiency. I *believe* that automobiles are 30% - 40% efficient, meaning they turn 30-40% of tthe energy they use into motive force rather than heat. I too am not a physicist so add salt.

[island911]

chips are binary, with linear speeds.

IC motors are multi variable (non-linear thru range) . . but, somewhere here I posted a thermal efficiency chart. (as comp-ratios go up, so does performance. --tho' goes up non-linearly too )

[Dantilla]

Internal combustion engines have improved greatly, but at a much slower pace.

The Wright brothers were able to fly by squeezing twelve horsepower out of a 180 lb. engine- 15 lbs. per hp.

The new Corvette Z06's 500 hp engine weighs less than one lb per hp.

[svandamme]

binairy valvetrains are coming though...
they're working on it , pneumatic valves actuated by a computer , not a camshaft, so the valve opening can be digital , ON/OFF based on requirement, not based on the compromise cam grind

[FrayAdjacent911]

I was wondering about computer controlled valve systems.... If they're robust enough, I think they'd be great for making some mad power out of some engines, and could be really efficient in others. Direct injection will also help.

I think we have plenty of room to squeeze more out of gasoline... in terms of power and efficiency.

[svandamme]

from what i've read they're coming , along with a change to 48 volt battery's , since they are required to power the valve train


either way, those things should indeed provide a big leap forward, as the engine can then be controlled completely

tuning those buggers will become a new black art if you ask me
no longer a matter of ignition vs fuel , but valve control vs ignition timing, vs fuel delivery.... the amount of possible settings for a given situation grows significantly... i'm thinking that it won't be long before they'll have custom chips designed specifically to "learn" engine characteristics and driver habits... so the tune can adapt on the fly to whoever bought the car...

performance , yes , economy yes
but it'll probably be terribly booooooooring.
coupled to hybrid technology... just another step towards silently buzzing electrectical cars...

i'm not looking forward to the day when a 500CC hybrid with above valve technology becomes the standard...

[Dantilla]

Originally posted by svandamme

i'm not looking forward to the day when a 500CC hybrid with above valve technology becomes the standard...

As long as the performance rivals, or exceeds currently available sports cars, I'm okay with it. I doubt the sound track will be as nice, however......

[IROC]

Originally posted by FrayAdjacent911
I think we have plenty of room to squeeze more out of gasoline... in terms of power and efficiency.

I've often looked at this from another angle. Using basic physics (no, I'm not a physicist but I had to endure alot of it in college), a certain amount of energy is always going to be required to accelerate a given mass at a given rate.

The problem we have these days is that cars (and SUVs) have gotten very heavy. The laws of physics dictate that if we want to accelerate these things quickly (and we seem to enjoy doing that), then it's going to take alot of energy - no way around it. Heck, today's 911s weigh 1000lbs (!!!) more than they did 30 years ago. That's shocking.

Gasoline only has so much energy in it. There are limits to how efficiently we can extract that energy. IMHO, we need to focus on building lighter-weight (but safe) cars that don't require so much energy to move around.

My very first car - a 1978 Mazda GLC - got 40mpg. 40mpg!! In 1978! And it was nothing special. How many cars get 40mpg these days? I previously owned a 1983 Toyota 4WD pickup. 96hp out of a 2.4 liter engine. It got over 26mpg on the interstate and was perfectly acceptable. Now, Toyota (catering to the *needs* of the US drivers) is hard-pressed to offer a 4WD pickup with less than 245hp. The fact that you can get around 20mpg out of today's Toyota on the interstate is a testament to increases in efficiencies, but it also hints at what is possible if 200+ hp wasn't *required* in today's market...

I think we need to shift our focus to smaller, lighter-weight vehicles that have reasonable power outputs.

Mike

[kach22i]

Originally posted by svandamme
from what i've read they're coming , along with a change to 48 volt battery's , since they are required to power the valve train

I read about this a couple of years ago, when will it take place?

[svandamme]

magnetti marelli had something on one of their websites, can't find the link no more,it stated they have the basics working , but need to refine it before it becomes practical and reliable enough for full blown production cars...

here's a link to some schematics, not the link where i read the full explanation though...

http://www.marelliusa.com/new_developments_2.html

[sketchers356]

Originally posted by svandamme
i'm thinking that it won't be long before they'll have custom chips designed specifically to "learn" engine characteristics and driver habits... so the tune can adapt on the fly to whoever bought the car...

My Ford Taurus does this as do most all current cars.
Oh and I am a physicist, not that I study engines, but as a side note it will be interesting if computer chips will be able to keep up with Moore's law. It is dificult to build gates that are less than one atom wide, which is where we will be in less than 5 years unless we have a radical switch in process. One can only build a chip so large, and its components so small...
I am really excited about the electronic valves though. I think that it is a great idea. This could take v-tec up several levels. Also, this could cause the bottom end to be the limiting factor for redline.

[island911]

Originally posted by Wayne at Pelican Parts
As an MIT-trained Mechanical Engineer, I have always been disappointed in the lack of progress that I feel the automotive companies of the world have made in engine technology. Let's face it, engines today are almost exactly the same as they were in the 1920s. The only radical concept to come out in the past few decades was the rotary engine - a design that was truly superior in simplicity, but didn't receive enough research and development to meet stringent emissions requirements.

. . snip...

-Wayne

Well, As a NON-MIT-trained Mechanical Engineer, I have always been disappointed MIT-trained Mechanical Engineers who believe that the rotary engine didn't receive enough research and development.

I studied under two phd engineers (different schools) who studied the Wankle for aircraft applications (one for US, one for Germany)-- both had the same conclusions. That is, a rotory engine, by it's very defining geometry, does a very poor job of "capturing the bang."

...this leads to poor emissions, and blown weight savings (all the extra fuel need to be carried)

[island911]

Originally posted by nostatic
... But just take power to weight ratio. I assume it’s improved a lot. ..

just look up in the sky. A couple of turbojet engines lift hundreds of people (and all their crap) and whisk them of to far away places.

Even better (pwr/weight) than the turbojet, is the scramjet. Hopefully we'll see more application of that technology.

[IROC]

I read in AutoWeek where some guy has come up with a 6-stroke engine. Maybe he's on to something...

Mike

[svandamme]

Originally posted by IROC
I read in AutoWeek where some guy has come up with a 6-stroke engine. Maybe he's on to something...

Mike

http://curriculum.wcape.school.za/resource_files/110084437_Beare_6_Stroke_Engine.rtf

no schematics though , have a hard time visualising the thing from that text...

just found this

[island911]

from what I can gather, it has a 2-stroke (piston ported) as the "slide valve" for the 4-stroke below it.

Rube Goldberg called, he wants his overly complicated device back.

[FrayAdjacent911]

Originally posted by svandamme
http://curriculum.wcape.school.za/resource_files/110084437_Beare_6_Stroke_Engine.rtf

no schematics though , have a hard time visualising the thing from that text...

just found this

Yep, looks like the upper piston cycles twice in the four strokes of the main piston. The top piston comes down on the compression stroke, possibly allowing for more fuel/air, and higher compression.

Seems to me like that might work, but might need higher octane fuel to avoid detonation. Also having another piston makes the engine bigger, and heavier. Also internal losses from more parts having to be moved... I would be interesting to see how much more efficient it could be.

[svandamme]

from the looks of it, it doesn't seem ideal for bigger engines, you need a disk per cyllinder, at least that's how i interpreted the setup
single jug, yeah, V twin sure... V4 or flat 4, possible

but imagine this on a flat 6 or V8 , never mind V10's or V12's

you'de have disks everywhere
and the port would have to be routed... cyllinder spacing?? how would that work out?? at best it would work ,but i'm sure it wouldn't be s3xy